Authors:

Jeongsu Lee(State Univ of NY - Buffalo)

Karel Vyborny(Institute of Physics ASCR)

Jong Han(State Univ of NY - Buffalo)

Igor Zutic(State Univ of NY - Buffalo)

Unlike the common expectation, theoretical calculations in quantum wires and
quantum dots have predicted hole ground state wavefunctions with a node
[1-2] that are often associated with the formation of dark excitons [3]. The
inversion of the energy level ordering between nodeless (S-like) and nodal
(P-like) wavefunction states occurs due to various factors, e.g.,
confinement size and strength, choice of a material, and spin-orbit
interaction. However, the existence of the nodal ground states has been
debated and even viewed merely as an artifact of a k\textbullet p model [4].
Using complementary approaches of both k\textbullet p and tight-binding
models, further supported by an effective Hamiltonian for a continuum model,
we reveal that the nodal ground states in quantum dots are not limited to a
specific theoretical model. Remarkably, the emergence of the nodal ground
states can be attributed to the formation of the orbital vortex textures
that minimizes ``divergence''. We discuss how our findings and the studies
of orbital textures could be also relevant for different materials systems.
[1] K. V\'{y}born\'{y} et al., PRB 85, 155312 (2012)
[2] A. Bagga et al., PRB 74, 035341 (2006); P. Horodysk\'{a} et al., PRB 81,
045301 (2010); J. Xia and J. Li, PRB 60, 11540 (1999); M. P. Persson and H.
Q. Xu, PRB 73, 125346 (2006).
[3] M. Nirmal, et al., PRL 75, 3728 (1995); Al. L. Efros, et al., PRB 54,
4843 (1996).
[4] L. W. Wang et al., APL 76, 339 (2000)

*This work was supported by the DOE-BES DE-SC0004890, NSF-DMR 0907150, and US ONR.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2014.MAR.Y8.3